The present invention relates in general to motor vehicle headlights, and more particularly to an accessory headlight capable of selectively generating two distinct types of beam, e.g. both a moving or xe2x80x9ccorneringxe2x80x9d beam for lighting the road while taking account of corners taken by the vehicle, and also a different beam, e.g. of the fog light type.
Accessory headlights for fitting to most up-market or middle-market vehicles already include headlights that generate a cornering beam; conventionally they comprise both a reflector co-operating with a light source such as a filament lamp to generate a xe2x80x9ccorneringxe2x80x9d beam, the reflector being mounted to pivot about a generally vertical axis, and displacement means that are provided to servo-control the angular position of the reflector, e.g. as a function of the position of the vehicle steering wheel.
Headlight units are also known that combine within a single housing both a cornering headlight and a fog headlight.
Thus, document FR-A-2 626 625 describes a headlight unit comprising a single light source which co-operates both with a fixed first reflector of large size for forming a fog light beam, and with a second reflector rotatably mounted within the first reflector for generating a cornering type beam.
Also known, from document FR-A-2 577 014, is a headlight unit similar to the above in which the glass is designed to deflect differently rays coming from the moving reflector and rays coming from the fixed reflector.
Those two known headlights serve to modify a conventional fog light beam so as to direct a portion of the light to one side of the road or the other as a function of the cornering of the vehicle. It is in that respect that they merely constitute adaptive fog headlights.
However, such known headlights do not in any way make it possible selectively to obtain either a fixed fog light beam in compliance with regulations, or else a genuine cornering beam, e.g. usable together with a conventional dipped beam.
In addition, a genuine cornering beam, of the kind now widely accepted in the motor industry, must present a lateral spread of about xc2x120xc2x0, defined on top by a horizontal cutoff, and presenting on its axis maximum illumination of at least 20 lux to 25 lux at a distance of 25 meters ahead of the vehicle. Neither of the two above-mentioned documents enables such an object to be achieved, with variations in the light necessarily being xe2x80x9cdrownedxe2x80x9d in the conventional fog light beam.
In this respect, it will be observed that the above-defined cornering beam differs from a conventional fog light beam by substantially smaller spread and by range, as defined by a central concentration spot, which is much longer.
The present invention seeks to improve prior art cornering headlights, and in particular to take advantage of the characteristics of a cornering headlight to make another type of beam available on request and separately, by using means that are simple, low cost, and easy to implement industrially, for example a fixed fog light beam complying with photometric regulations. In addition, the present invention seeks to provide a headlight in which the number of components implemented remains limited, with the advantages of being compact, very simple to assemble, and reasonable in cost.
To this end, the invention provides a motor vehicle light comprising a light source mounted in a reflector and a glass, the reflector being mounted to pivot about a generally vertical axis, and displacement means being provided to vary the angular position of the reflector, the headlight being characterized in that the reflector is capable of occupying at least one first angular position in which the beam emitted thereby passes through a first glass to generate a first type of beam, and a second angular position which is fixed and different from the first angular position(s), and in which the beam passes through a second glass, and in that the headlight also comprises optical means for generating through said second glass a fixed beam which has photometric characteristics different from those of the beam generated through the first glass.
Preferred but non-limiting features of the headlight of the invention are as follows:
the first and second glasses extend one from the other;
the first and second glasses are made as a single piece;
the first glass extends ahead of the second glass which then constitutes an intermediate screen between the reflector and the first glass;
said angular positions and the positions of the two glasses are selected so that each of the first and second glasses respectively receives solely the beam emitted by the reflector in the first angular position(s) and solely the beam emitted by the reflector in the second angular position;
the first glass is essentially smooth and its surface is oriented in such a manner as to attenuate reflection losses thereon;
the beam generated by the sole reflector is a laterally-spread cutoff beam;
the fixed beam is a beam of the fog light type;
said first angular position of the reflector is a single position;
said displacement means are suitable for varying said first angular position of the reflector over a given range of angles as a function of the position of the vehicle steering wheel;
the optical means are suitable for spreading horizontally the light beam emitted by the reflector;
said second angular position is oblique relative to the axis of the vehicle and is situated on the opposite side of said axis to said first angular position, and said second glass directly receives the beam emitted by the reflector in the second angular position;
the optical means are provided on said second glass;
the second glass has rectifying means for rectifying the beam from the reflector when in said second angular position and for obtaining a beam of mean direction that is substantially parallel to the axis of the vehicle;
the optical means for spreading and the rectifying means are constituted by the same optical arrangements;
said second angular position is essentially transverse relative to the axis of the vehicle and is situated on the opposite side of said axis to said first angular position, and said second glass receives the beam emitted by the reflector when in the second angular position via a deflector mirror; and
the optical means are provided either on said second glass or on the deflector mirror.
Other features, objects, and advantages of the present invention will appear more clearly on reading the following detailed description of a preferred embodiment thereof, given by way of example and with reference to the accompanying drawings, in which: